Correlation at zero lag with r_{crit} (95%) in parentheses (upper triangle) and maximum correlation with lead in parentheses (lower triangle) for the variables Niño-3.4, −ESOI, , η_{E}, , , and . For example, the correlation is maximum between η_{E} and Niño-3.4 (r = 0.76) when η_{E} lags Niño-3.4 by −1 month, i.e., it leads Niño-3.4 by 1 month. Wind stress anomaly data in the table were taken from the website http://apps.ecmwf.int/datasets/data/interim-full-moda/levtype=sfc/. All data have been filtered with a 5-month running mean. The RMS values of each of the time series used are Niño-3.4 (0.86°C), −ESOI (0.9280), (7.3 mPa),η_{E} (5.82 cm), (3.9 mPa), (2.4 mPa), and (4.39 cm). Variable H_{1} = 118 m is defined from the regression between η_{E} and [see (22) of the main text with L corresponding to the equatorial distance between 139.5°E and 82.5°W, g = 9.8 m s^{−2}, and ]. Since both sides of (22) have noise, the regression coefficient was calculated using the ratio of standard deviations (Clarke and Van Gorder 2013).